1. Field of the Invention
The present invention relates to a system and a method for determining an abnormal operating condition in the speed ratios of an automatic transmission. More particularly, the present invention relates to a device and a method for determining an abnormal operating condition in the speed ratios of an automatic transmission that can easily sense a mechanical problem with the automatic transmission.
2. Description of Related Art
Generally, an automotive vehicle including an automatic transmission may control the flow of fluid within a speed ratio range that is predetermined according to the running speed of the vehicle to automatically shift a transmission gear to a desired speed ratio.
That is, a torque converter uses power produced by an engine to control the torque of the fluid. The fluid acts on a valve corresponding to a control signal supplied from a transmission control device to operate the transmission gear according to the operating state of the vehicle.
In an automotive vehicle having such an automatic transmission, operation of a clutch pedal for cutting off power from the engine is not necessary to vary the transmission gears being in mesh. Since the engine stall by a driver's misoperation and poor driving capability does not occur, even a beginner may easily drive a car.
An automatic transmission, having speed ratios that vary considerably depending on the running condition of the vehicle has an exceedingly complicated structure. Thus, where an abnormal operating condition occurs somewhere in the transmission and a normal shift operation is not performed, a lot of time and effort is required to find the exact problem in the system and repair it.
Conventionally, if the automatic transmission does not operate normally, the transmission is replaced with a new one instead of performing a repair. Thus, this causes a financial burden to a driver.